In the prior art, as shown for example in U.S. Pat. No. 8,735,846, a biosensor disk may have a spiral data path encoded with digital data. The data is established by a sequence of pits and lands on the surface of the disk. As the disk is rotated in a reading system, light from a laser or light emitting diode is directed onto the disk at the spiral data path. The system reads the encoded data as indicated by the light reflected from the pits and lands.
The disk further has detector chambers for containing analytes. Ligands are provided to bind specific analytes in place within the chambers. The detector chambers are interposed between the reader system and the spiral data path such that analytes in the chambers can obscure the transmission of light to and from the data path. Accordingly, alterations in the data read by the system indicate the presence of the specific analytes corresponding to the ligands in the chambers where the data path is obscured.